Respiratory Failure Flashcards
What is the goal of the respiratory system?
The goal of the respiratory system is to provide the body an adequate oxygen supply for cellular metabolism and to remove the body’s major metabolic waste product: carbon dioxide.
What three mechanisms is respiration accomplished by?
- Ventilation 2. Diffusion 3. Circulation/Perfusion
What is respiratory failure defined as?
Impaired gas exchange Normally defined as: PaO2 < 50mmHg Hypoxemia PaCO2 > 50mmHg Hypercarbia
What things lead to hypoxemia? Hypercapnia?
What are the classifications of Respiratory failure?
- Acute 2. Chronic 3. Acute on Chronic
Hypercapnia is associated with what finding?
Respiratory acidosis
What are common diseases that lead to hypoxia?
conducting airways asthma,
pneumonia, pulmonary emobolism
Explain acute respiratory failure for both hypercapnia and hypoxemia?
Acute
Minutes to hours; no compensatory changes
Explain chronic respiratory failure for both hypercapnia and hypoxemia?
Hypercapnia Days to months; compensatory mechanisms present are increase pH and increase HCO3
Hypoxemia: Days- months compensatory mechanism present is increase in hemoglobin
What diseases could lead to acute? chronic? and acute on chronic respiratory failure?
What are the classifcations of respiratory failure?
Type I Hypoxemic PaO2 < 50 at sea level
Type II Hypercapnic +/- Hypoxemic PaCO2 > 45
Other: Type III Perioperative
Type IV Shock
What are the four mechanisms hypoxemic respiratory failure might happen due to?
A. Ventilator/Perfusion Inequality (V/Q)
B. Shunt
C. Hypoventilation
D. Diffusion Impairment
*Rarely low FIO2
Findings associated with hypoventilation?
- Increased PACO2 and PaCO2
- Decreased PAO2 and PaO2
- Normal P (A-a) O2 gradient when it occurs acutely
- PAO2 and PaO2 (but not the hypoventilation) can be corrected by raising FIO2
Findings associated with a shunt?
- Causes a fall in PaO2
- Results in a increased P (A-a) O2 gradient
- Responds poorly to increased FIO2
- Measure clinical on 100% O2
Findings seen with a Low ventilation/perfusion mismatch?
- Causes a decreased PaO2 due to low V/Q alveoli
- Usually associated with a normal PaCO2
- Associated with an increased P (A-a) O2 gradient
- Characteristically responds well to small increases in FIO2 5. Completely corrected by 100% oxygen